Magnetic-Exchange Effects

As it relates to upconversion, this NE+-Mn + exchange interaction enhances both Oq for GSA and Oi for ESA in Eq. (6), since both relate to strongly spin-forbidden processes in the single ion, and both increase several fold upon interaction with Mn [75]. The exchange interactions affect the spin-forbidden intensities most dramatically since these begin with little intensity and their descrip- 

---

Binsch G 1969 A unified theory of exchange effects on nuclear magnetic resonance lineshapes J. Am. Chem. Soc. 91 1304-9... 

Mogi, I. (1996) Magnetic field effects on the dopant-exchange process in polypyrrole. Bull. Chem. Soc. Jpn., 69, 2661—2666. 

Finally, we discuss the effects of chalcogen (S to Se) substitution. Although in (EDS-TTF)2FeBr4 remarkably close Se---Br contacts exist between donor and anion layers, little magnetic exchange interaction exists between the magnetic anions. The molecular orbital calculation reveals that the contribution of Se 4p orbital to the HOMO of the EDS-TTF molecule is considerably smaller than the contribution of... 

Abstract This review deals with spin crossover effects in small polynuclear clusters, particularly dinuclear species, and in extended network molecular materials, some of which have interpenetrated network structures. Fe(II)Fe(II) species are the main focus but Co(II)Co(II) compounds are included. The sections on dinuclear compounds include short background reviews on (i) synergism of SCO and spin-spin magnetic exchange (ii) cooperativity (memory effects) in polynuclear compounds, and (iii) the design of dinu-... 

The EPR data are of course intimately related to magnetic susceptibility data. The Weiss constant of the 5-phase is proportional to D which will amount to only a few degrees Kelvin at most, while the Weiss constant of the /8-phase is large due to the large exchange effects in this phase. The Weiss constant obtained from a magnetic susceptibility measurement is thus due predominantly to the /8-phase. 

Though the true electron spin operators were employed here as well as in the Breit-Pauli Hamiltonian, the phenomenological Spin Hamiltonian, in which the spin coupling is an exchange effect, is in sharp contrast to the Breit-Pauli Hamiltonian, that is including the (magnetic) spin-spin interactions. Since the exchange effect is an effect introduced by the Pauli principle imposed on the wave function, we may write the electron-electron interaction as an expectation value,... 

---